WASHINGTON — The courier who led the CIA to Osama bin Laden’s doorstep was identified through years of painstaking detective work that included developing a composite “profile” of what an ideal courier for the al-Qaida leader would look like.

“It was like doing the profile of a serial killer,” said one U.S. official, who provided new details to NBC News about how the agency was able to track down the courier and, ultimately, bin Laden himself. The official, who spoke on the condition of anonymity, was one of the three U.S. officials to describe the intelligence community's search for the courier.

As agency analysts sifted through tantalizing bits of information about bin Laden’s longtime aides in 2002, the official said, they concluded that one in particular — Shaykh Abu Ahmed al Kuwaiti, matched many of the attributes contained in their composite portrait.

As a Pakistani Pashtun, Abu Ahmed spoke Pashto. Having grown up in Kuwait in the Persian Gulf, he also spoke fluent Arabic. That meant he could communicate and move easily among both the “Afghan Arabs” who had flocked to Afghanistan in the 1990s to join al-Qaida and the Pakistani tribesman suspected of harboring bin Laden.

Moreover, Abu Ahmed had been described by detainees as having been a trusted protégé of Khalid Sheikh Mohammed, al-Qaida’s No. 3 commander, as well as a top aide to Mohammed’s replacement, Abu Faraj Al Libi. Abu Ahmed, who was adept at the use of computers, had been with al-Qaida for years and appeared to be fiercely loyal to bin Laden’s cause. He was described by multiple detainees at the Guantanamo Bay detention camp as having last been seen by bin Laden’s side when the al-Qaida leader vanished through the mountains of Tora Bora in December 2001.

'He fit all the needs'
The CIA had concluded that any still active courier for bin Laden would have to meet the most extreme of loyalty tests. That meant he would likely have been serving bin Laden well before the Sept. 11, 2001, terrorist attacks against the U.S.

That “match” between the known details about Abu Ahmed’s background and the composite agency profile helped CIA officials cut through multiple conflicting accounts — and considerable misinformation — about the identity of bin Laden’s courier, the official said.

Once the match was made, the official said, analysts intensified their hunt for Abu Ahmed. If they could find Abu Ahmed, they reasoned, they just might be able to find bin Laden himself.

The information about the use of “profiling” fleshes out the story of how agency officials were finally able to locate bin Laden after a frustrating search that spanned nearly a decade. Those and other new details would appear to conflict with claims in recent days that waterboarding or other “enhanced interrogation techniques” produced some blockbuster piece of information that led to bin Laden’s death.

A mysterious, well-placed Kuwaiti
The story began in late 2002, when detainees at Guantanamo described a mysterious Kuwaiti man who seemed to be in bin Laden’s inner circle. As first reported by NBC, one of the first — if not the first — to do so was Mohammed Qahtani, the suspected 20th hijacker for the 9/11 attacks, who tried but failed to enter the U.S. at the Orlando airport in August 2001.

A Defense Department Joint Task Force assessment of Qahtani, released last month by WikiLeaks, describes the information provided by the prisoner they called “Maad al-Qahtani” after abusive interrogations that were later described by one senior Bush administration official as meeting the legal definition of torture.

The document contains multiple references to his interactions with a mysterious al-Qaida operative identified as “Abu Ahmad al-Kuwaiti.” The document states that before being dispatched to board a plane to Orlando, Qahtani received computer training in Karachi, Pakistan, from the Kuwaiti operative "for his mission to the United States."

The document further states that Qahtani told interrogators that Khalid Sheikh Mohammed had directed Al-Kuwaiti to teach him how to use email and had taken him to an Internet café for his training. The Kuwaiti operative is further described in the document as a “senior al-Qaida facilitator” and “courier” who was a subordinate to Mohammed.

The document includes this note: “Al Kuwaiti was seen in Tora Bora and it is possible al-Kuwaiti was one of the individuals … accompanying UBL (Osama bin Laden) in Tora Bora prior to UBL’s disappearance.”

When U.S. intelligence officials first heard this information in late 2002 and early 2003, they had no idea who “Al Kuwaiti” really was. And they soon received conflicting reports that threw them off the trail.

Did harsh interrogations work?
Because U.S. military officials later concluded that Qahtani was subjected to abusive and “degrading” interrogations — including being chained to a leash and forced to perform dog tricks — his case could provide ammunition to defenders of such methods.

But Defense Department records and interviews with U.S. officials show that three other detainees who were also subjected to extremely rough interrogations provided misleading or false information about the Kuwaiti courier.

One of them, according to documents reviewed by NBC News, was Mohamedou Ould Slahi, a Mauritanian who had been active in Islamic militant circles in Germany and who, according to the 9/11 commission report, had encouraged three of the 9/11 hijackers to fly to Afghanistan for training.

Slahi, according to two government reports, was subjected to steadily escalating rough interrogations approved by Secretary of Defense Donald Rumsfeld. Among them: being threatened with death, deprived of sleep, exposed to “variable lighting patterns” and subjected to blasting rock music, including Drowning Pool’s “Bodies,” with its chorus of “Let the bodies hit the floor!” according to a detailed account in the Washington Post.

Yet when Slahi was questioned about the Kuwaiti courier, he told a story that turned out to be false: He reported that Abu Ahmed “was wounded while fleeing Tora Bora and later died in the arms” of another detainee, according to this Defense Department Document.

When Khalid Sheikh Mohammed was captured in Pakistan in early 2003, he was flown to a CIA black site prison in Poland and waterboarded 183 times. At first, he wasn’t even asked about Abu Ahmed. When he was months later, he described Abu Ahmed as a minor figure who was “retired,” said the U.S. official. “He played down his significance.” He was, said another U.S. official, protecting Abu Ahmed, refusing to give up “the crown jewels.”

No such person
In 2005, when the CIA captured Mohammed’s replacement, Abu Faraj Al-Libi, and subjected him to “enhanced interrogation techniques,” he too misled his interrogators, two U.S. officials said. He told them that bin Laden’s “designated” courier and “official messenger” was another man: Malawi Abd al Khaliq Jan. CIA officials later concluded that no such person even existed — and that Al Libi, like Mohammed, was trying to conceal Abu Ahmed’s role in order to protect bin Laden.

As first reported by The New York Times, to the extent that there was a breakthrough, it came from the interrogation of yet another al-Qaida detainee, Hassan Ghul. Ghul, who had been captured in Iraq in 2004 and who may have also been subjected to some rough interrogations (but not waterboarding), described Abu Ahmed as a “trusted” messenger of bin Laden who was extremely close to Mohammed and al Libi and who had “disappeared.” By late 2005, the sharp discrepancies with their accounts caught the attention of agency interrogators and caused them to redouble their efforts to figure out Abu Ahmed’s identity.

When they did, they began to match up the slivers of details about him from multiple detainees with the agency’s internal “profile” of a bin Laden courier and were struck by the match, the U.S. official said.

But it wasn’t until 2007 — four years after Mohammed had been waterboarded — that they were able to figure out his identity. And it wasn’t until 2009 that they were able to locate him in Pakistan, thanks to electronic intercepts of cell phone calls and emails. At that point, Pakistani operatives working for the CIA began to trail him and eventually traced him to the compound in Abbottabad where he and the al-Qaida leader were killed on Sunday.

"If it really had been waterboarding that had produced the key piece of information that led us to Osama bin Laden," one U.S. official said, "we would have been having this conversation years earlier — not in 2011."

Video: Curious neighbors peer into bin Laden compound

Closed captioning of: Curious neighbors peer into bin Laden compound

>>let's go to the scene of the raid in pakistan where
high level
officials arrived at the compound north of islamabad. tonight, there are more pictures from inside the hideout where the s.e.a.l.s made the raid that killed
osama bin laden
. stephanie gosk is there for us tonight.

>> reporter: a look inside the hideout. ransacked and definitely lot luxurious. everyday belongings mixed in with the aftermath of a bloody struggle, including a yemeni passport apparently belonging to
bin laden
's fifth and youngest wife. this video was shot not long after the precision assault sunday by
u.s. navy
s.e.a.l.s. what happened in this house that night and the years leading up to it has captivated the world and shocked the people who actually live here. today, a homeowner next door briefly gave access to his roofp roofptop. dozens of neighbors climbed up, eager to see what they could. this is one of the best views we have had of the compound. the house is large, but really, in comparison to the other houses in the neighborhood, it's not that big. there's a rumor that
security forces
are eventually going to destroy it. residents are sharing what they rer78 of two brothers, owners of the house. they used to come to these small shops buying milk and pepsi, often in bulk. we now know one of them was the infamous courier faollowed for years. this man remembered seeing the brothers in town but never the wives.

>>did the women ever and out of the house?

>>no, no women. you don't see here the women.

>> reporter: many people here don't believe
bin laden
was killed. they don't even believe he was here. does anyone here believe that
osama bin laden
was in that house? nobody? overhead today, helicopters flew by. not a rare sight in a military town, but when they heard the sound of choppers late sunday night, it didn't sound right. he started tweeting, having no idea what was really happening. helicopter hof eer hovering over aboughta bod at
1:00 a.m
. is a rare event. go away. i hope it's not the start of something nasty. he wads the only person reporting the capture of
bin laden
as it happened. how many followers did you have on twitter on that moment?

>>almost 800, 900.

>>now how many do you have?

>>more than 100,000.

>> reporter: an instant
internet celebrity
who moved his family here from lahore last year to escape the terrorists.

>>i came here to escape all the bombings and now i find myself living in the same town as him.

>>a
small town
once far removed from the fight on terrorism. now the site of one of its most important battles. nbc news pentagon correspondent
jim miklaszewski
reports that u.s. officials are providing a clearing picture of the firefight that happened here. it wasn't an intense back and forth but mostly one-sided. mostly the s.e.a.l.s doing the shooting. a proscission-clearing operation.

An aerial view shows the residential area of Abbottabad, Pakistan, where Osama bin Laden was found and killed by U.S. commandos.
(Asif Hassan / AFP - Getty Images)
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A general view of the town of Abbottabad, May 6. Bin Laden was living in a large house close to a military academy in this garrison town, a two-and-a-half hour-drive from the capital, Islamabad.
(Khaqan Khawer / EPA)
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Supporters of Pakistani religious party Jamaat-e-Islami rally to condemn the killing of bin Laden, in Abbottabad on May 6.
(Aqeel Ahmed / AP)
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A Pakistani woman photographs her daughter on May , at a gate of the compound where bin Laden was caught and killed.
(Aqeel Ahmed / AP)
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School girls pass by armed Pakistani policemen guarding the sealed entrance to the compound in Abbottabad, May 5, in which bin Laden had been living.
(MD Nadeem / EPA)
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A Pakistani police officer gestures at a checkpoint along a road leading to a house where bin Laden was captured and killed in Abbottabad. Area residents were still confused and suspicious about bin Laden's death, which took place before dawn on Monday.
(Anjum Naveed / AP)
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Part of a damaged U.S. MH-60 helicopter lies the compound. The helicopter was destroyed by U.S. forces after a mechanical failure left it unable to take off.
(Reuters)
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A still image from video obtained by ABC News shows blood stains in the interior of the house where bin Laden was killed.
(ABC News via Reuters)
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Aerial views released by the Department of Defense show the area in Abbottabad in 2004, left, before the house was built, and in 2011, right.
(Department of Defense via Reuters)
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Boys collect pieces of metal from a wheat field outside bin Laden's house, seen in the background, on May 3. People showed off small parts of what appeared to be a U.S. helicopter that the U.S. says malfunctioned and was blown up by the American team as it retreated.
(Anjum Naveed / AP)
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An image from video seized from the walled compound of al-Qaida leader Osama bin Laden in Abbottabad, and released by the U.S. Department of Defense, shows Osama bin Laden watching TV. He is said to have spent his last weeks in a house divided, amid wives riven by suspicions. On the top floor, sharing his bedroom, was his youngest wife and favorite. The trouble came when his eldest wife showed up and moved into the bedroom on the floor below.
(Department of Defense via AP)
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Editor's note:
This image contains graphic content that some viewers may find disturbing.

Timeline: A timeline of Osama bin Laden's life

Considered enemy No. 1 by the U.S., the Saudi millionaire is the perpetrator behind the Sept. 11, 2001, attacks. Click on key dates to learn more about the founder of al-Qaida, an international terror network.

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